1. Field of the Invention
The invention relates in general to plasma chambers and, more particularly, to a plasma chamber that has a wall temperature control system.
2. Description of Related Art
Plasma chambers may be used to contain plasma, for example, in a plasma semiconductor substrate processing tool. Typically, plasma ions are accelerated toward a semiconductor substrate within the plasma chamber. During the course of the process, ions, neutral particles, and contaminants are pumped out of the chamber while fresh gas is supplied and formed into plasma.
The chamber wall temperature affects the local surface chemistry, e.g. the nature and amounts of different chemical species adsorbed and emitted from the walls. These species in turn affect the local gas phase chemistry in the plasma, and thus the plasma process result, e.g. rate, selectivity, etc.
With the current trend of introducing in-situ chamber cleaning steps between wafer batches, fast ramp-up and ramp-down of wall temperatures can be advantageous.